I think the first and most important thing is that by us posting a poll, folks will assume that the winner is guaranteed to see action. If we say "What species would you like to see in SWTOR?" and Togruta wins, in your example. Everyone will assume we are definitely going to add Togruta to the game. Unfortunately, it just wouldn't work that way.
Thats what a poll is for, to see what the players want. I would assume that people who play the game and also use the forums are more active than people who dont care about anything and just play the game and never use the forums...
So basically we have no say in what goes in the game?